US4482004A - Waste heat boiler - Google Patents

Waste heat boiler Download PDF

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Publication number
US4482004A
US4482004A US05/849,987 US84998777A US4482004A US 4482004 A US4482004 A US 4482004A US 84998777 A US84998777 A US 84998777A US 4482004 A US4482004 A US 4482004A
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United States
Prior art keywords
heat
heat transfer
evaporator
steam
boiler tank
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Expired - Lifetime
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US05/849,987
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English (en)
Inventor
George M. Grover
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Alstom Power Inc
Qdot Corp
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Qdot Corp
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Publication date
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Priority to US05/849,987 priority Critical patent/US4482004A/en
Priority to JP3357978A priority patent/JPS5469854A/ja
Priority to FR7809345A priority patent/FR2408805A1/fr
Priority to DE19782820734 priority patent/DE2820734A1/de
Priority to CA315,907A priority patent/CA1123690A/fr
Priority to EP78101332A priority patent/EP0001844B1/fr
Priority to DE7878101332T priority patent/DE2862224D1/de
Priority to US06/496,234 priority patent/US4621681A/en
Application granted granted Critical
Publication of US4482004A publication Critical patent/US4482004A/en
Assigned to Q-DOT CORPORATION, A DE CORP. reassignment Q-DOT CORPORATION, A DE CORP. MERGER (SEE DOCUMENT FOR DETAILS). 2/7/85, DELAWARE Assignors: QDC HOLDINGS, INC., A DE CORP. (CHANGED TO), Q-DOT CORPORATION, A DE CORP. (MERGED INTO)
Assigned to ABB AIR PREHEATER, INC., A DE. CORP. reassignment ABB AIR PREHEATER, INC., A DE. CORP. ASSIGNMENT OF ASSIGNORS INTEREST. Assignors: Q-DOT CORPORATION
Anticipated expiration legal-status Critical
Expired - Lifetime legal-status Critical Current

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    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F28—HEAT EXCHANGE IN GENERAL
    • F28F—DETAILS OF HEAT-EXCHANGE AND HEAT-TRANSFER APPARATUS, OF GENERAL APPLICATION
    • F28F1/00—Tubular elements; Assemblies of tubular elements
    • F28F1/10—Tubular elements and assemblies thereof with means for increasing heat-transfer area, e.g. with fins, with projections, with recesses
    • F28F1/12—Tubular elements and assemblies thereof with means for increasing heat-transfer area, e.g. with fins, with projections, with recesses the means being only outside the tubular element
    • F28F1/24—Tubular elements and assemblies thereof with means for increasing heat-transfer area, e.g. with fins, with projections, with recesses the means being only outside the tubular element and extending transversely
    • F28F1/32—Tubular elements and assemblies thereof with means for increasing heat-transfer area, e.g. with fins, with projections, with recesses the means being only outside the tubular element and extending transversely the means having portions engaging further tubular elements
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F22—STEAM GENERATION
    • F22B—METHODS OF STEAM GENERATION; STEAM BOILERS
    • F22B1/00—Methods of steam generation characterised by form of heating method
    • F22B1/02—Methods of steam generation characterised by form of heating method by exploitation of the heat content of hot heat carriers
    • F22B1/16—Methods of steam generation characterised by form of heating method by exploitation of the heat content of hot heat carriers the heat carrier being hot liquid or hot vapour, e.g. waste liquid, waste vapour
    • F22B1/165—Methods of steam generation characterised by form of heating method by exploitation of the heat content of hot heat carriers the heat carrier being hot liquid or hot vapour, e.g. waste liquid, waste vapour using heat pipes
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F22—STEAM GENERATION
    • F22B—METHODS OF STEAM GENERATION; STEAM BOILERS
    • F22B1/00—Methods of steam generation characterised by form of heating method
    • F22B1/02—Methods of steam generation characterised by form of heating method by exploitation of the heat content of hot heat carriers
    • F22B1/18—Methods of steam generation characterised by form of heating method by exploitation of the heat content of hot heat carriers the heat carrier being a hot gas, e.g. waste gas such as exhaust gas of internal-combustion engines
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F28—HEAT EXCHANGE IN GENERAL
    • F28D—HEAT-EXCHANGE APPARATUS, NOT PROVIDED FOR IN ANOTHER SUBCLASS, IN WHICH THE HEAT-EXCHANGE MEDIA DO NOT COME INTO DIRECT CONTACT
    • F28D15/00—Heat-exchange apparatus with the intermediate heat-transfer medium in closed tubes passing into or through the conduit walls ; Heat-exchange apparatus employing intermediate heat-transfer medium or bodies
    • F28D15/02—Heat-exchange apparatus with the intermediate heat-transfer medium in closed tubes passing into or through the conduit walls ; Heat-exchange apparatus employing intermediate heat-transfer medium or bodies in which the medium condenses and evaporates, e.g. heat pipes
    • F28D15/0275—Arrangements for coupling heat-pipes together or with other structures, e.g. with base blocks; Heat pipe cores
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F28—HEAT EXCHANGE IN GENERAL
    • F28D—HEAT-EXCHANGE APPARATUS, NOT PROVIDED FOR IN ANOTHER SUBCLASS, IN WHICH THE HEAT-EXCHANGE MEDIA DO NOT COME INTO DIRECT CONTACT
    • F28D21/00—Heat-exchange apparatus not covered by any of the groups F28D1/00 - F28D20/00
    • F28D21/0001—Recuperative heat exchangers
    • F28D21/0003—Recuperative heat exchangers the heat being recuperated from exhaust gases
    • F28D21/001—Recuperative heat exchangers the heat being recuperated from exhaust gases for thermal power plants or industrial processes
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F28—HEAT EXCHANGE IN GENERAL
    • F28F—DETAILS OF HEAT-EXCHANGE AND HEAT-TRANSFER APPARATUS, OF GENERAL APPLICATION
    • F28F2215/00—Fins
    • F28F2215/04—Assemblies of fins having different features, e.g. with different fin densities
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02P—CLIMATE CHANGE MITIGATION TECHNOLOGIES IN THE PRODUCTION OR PROCESSING OF GOODS
    • Y02P80/00—Climate change mitigation technologies for sector-wide applications
    • Y02P80/10—Efficient use of energy, e.g. using compressed air or pressurized fluid as energy carrier
    • Y02P80/15—On-site combined power, heat or cool generation or distribution, e.g. combined heat and power [CHP] supply

Definitions

  • the present invention relates generally to heat exchange systems, and in particular, to a gas-to-water heat recovery system which utilizes an array of heat pipes for collecting heat from a stream of heated gas and transferring the heat into a volume of water for the production of steam.
  • Heat recovery from industrial waste gas sources presents an ever increasing opportunity for economical operation of thermal systems.
  • the economic advantage from any form of heat recovery depends upon the availability and cost of fuels. Obviously, savings from heat recovery increase as fuel costs rise. As the cost of energy constantly increases, different types of systems and methods are being devised to recover and transfer energy which would otherwise be lost.
  • Conventional heat exchange apparatus operates in several heat recovery modes including air to gas, gas to water, and gas to organic fluids.
  • the selection of the mode of heat recovery depends upon the characteristics of the application, the processes used by the particular industrial facility, and the economic need for a given service. For example, steam can be generated at low pressure for heating or absorption air conditioning applications, at medium pressures for processing, or at higher pressures with or without superheat for electrical power generation.
  • the multiple drum natural circulation boiler is stable, the boiling heat transfers coefficients are high, and the system has reserve water for variable demand.
  • the several disadvantages inherent in this arrangement are an excessive number of tubes required for the downcomers, bent tubes are required in order to accommodate differential expansion, and the boiler drums must be thick walled for high pressure operation.
  • the rate of heat transfer from waste gases to the boiler water depends upon the temperature and specific heat of the gases, the velocity and direction of the gases over the heat absorbing surfaces of the boiler, and the cleanliness of the surfaces.
  • For proper heat transfer from the waste gases to the boiler water there must be sufficient stack or an induced draft fan to overcome the draft losses due to the required flow of the gases over the heat absorbing surfaces with an allowance for fouling of these surfaces.
  • the gas temperatures are generally lower and consequently the radiation component in the heat transfer mechanisme is also lower. Therefore, the tendency with waste heat boilers is to design for higher gas velocity over the tubes in order to increase the convection component of heat transfer.
  • the present invention concerns a method and apparatus for utilizing heat pipes in combination with a steam boiler for the recovery and transfer of thermal energy in a waste heat recovery system which operates effectively at low flow velocities.
  • Heat pipes normally comprise a sealed envelope which contains a working fluid having both a liquid phase and a vapor phase in the desired range of operating temperatures. When one portion of the heat pipe is exposed to a relatively higher temperature, it functions as an evaporator section. The working fluid is vaporized in the evaporator section and flows in the vapor phase to the relatively lower temperature section of the envelope, which becomes a condenser section. The working fluid is condensed in the condenser section resulting in the transfer of thermal energy due to the phase changes of the working fluid. The condensed working fluid is then transported in a liquid phase back to the evaporator section where the process is repeated.
  • the use of heat pipes in combination with a steam boiler offers several advantages over conventional heat exchange arrangements.
  • the transducer characteristic of the heat pipe permits collection of heat from a diffused source such as low velocity waste gas and transfer of the heat into a concentrated thermal sink such as a volume of water.
  • the simplicity of sealing a heat pipe through a single or double wall header plate provides complete isolation of one fluid stream from the other. Because of the single point connection, both the evaporator and condenser ends of the heat pipe extend freely thereby minimizing stress problems due to thermal expansion and contraction.
  • the outside of the heat pipe is available in both fluid streams for cleaning, for extended surface fin structure, or for special surface preparation to enhance heat transfer.
  • Heat pipes are utilized in the present invention to recover and transfer heat energy from a stream of heated waste gas to a volume of water disposed in a boiler for the production of heated water under pressure or for the production of steam.
  • the stream of heated waste gas is caused to flow through a convection heat transfer chamber where it is contacted by the evaporator portion of one or more heat pipes which connect the convection heat transfer chamber in thermal communication with a boiler in which a volume is disposed.
  • the condenser end of each heat pipe projects through a header plate disposed in a side portion of the boiler tank in thermal relation with the volume of water diposed therein.
  • a working fluid is disposed within each of the heat pipes which is characterized by a thermodynamic cycle in which the working fluid assumes the vapor phase in response to the transfer of heat energy from the heated gas phase through the evaporator section of the heat pipe, whereupon it flows from the evaporator section to the condenser section and assumes the liquid phase in the condenser section in response to the transfer of its heat energy through the condenser to the volume of water.
  • the transfer of thermal energy is substantially improved by elevating the condenser section above the evaporator section thereby permitting substantial volumes of unvaporized working fluid to be transported from the evaporator section to the condenser section.
  • a portion of the exhaust gas flow which is discharged from the convection heat transfer chamber after heat transfer has occured is circulated in a regenerative mode of operation in which the exhaust gas is directed into the input port of the convection heat transfer chamber for increasing the mass flow at a reduced velocity for optimum efficiency.
  • the regenerative mode of operation can also be used to good advantage to reduce the temperature of the heated waste gas flow when that temperature exceeds the operating limits of the working fluid of the heat pipes. In either case, the mass flow is increased thereby enhancing the transfer of heat in the evaporator section.
  • a superheat mode of operation is provided by connecting two or more convection heat transfer chambers in series fluid communication relation with each other.
  • Heat pipes connect the downstream convection heat transfer chamber in thermal communication with a steam boiler tank.
  • Steam produced by this arrangement is directed into the input of a second boiler tank where it is superheated by a second heat pipe assembly in which a condenser section is disposed within the second boiler tank in thermal relation to the stream of saturated steam and also having an evaporator section disposed in an upstream convection heat transfer chamber.
  • the heated gas stream first passes through the upstream convection heat transfer chamber at a given temperature for raising the saturated steam to a superheated level.
  • the flow of heated waste gas continues to the downstream convection heat transfer chamber at a lower temperature having sufficient heat energy for the generation of steam in the downstream boiler tank.
  • FIG. 1 is a perspective view of a waste heat recovery system constructed according to the teachings of the invention
  • FIG. 2 is a left side view, in section, taken along the lines II--II of FIG. 1;
  • FIG. 3 is a sectional view taken along the lines III--III of FIG. 2;
  • FIG. 4 is an isometric view of a portion of a heat pipe assembly utilized in the present invention.
  • FIG. 5 is a block diagram which illustrates a regenerative mode of operation of the present invention.
  • FIG. 6 is a block diagram which illustrates the combination of two heat recovery systems of the present invention in a superheat mode of operation.
  • the heat recovery system 10 includes a housing 11 which encloses a convection heat transfer chamber 12, a steam boiler tank 14, and a heat pipe assembly 16 which interconnects the convection heat transfer chamber 12 and steam boiler tank 14 in thermal communication with each other.
  • the housing 11 is equipped with an inlet port 18 through which a stream of heated waste gas, indicated by the arrow 20, flows into the convection heat transfer chamber 12 and across the heat pipe assembly 16 where thermal energy is transferred. After the thermal energy transfer has occurred, the exhaust gas flow is discharged through an exhaust port 22 to an exhaust stack by means of an induced draft fan (not shown).
  • the source for the heated waste gas stream 20 may be from any industrial process but for the purposes of the present discussion it will be assumed to be the exhaust from a gas turbine which is used in a total energy system to drive an alternator or a mechanical refrigeration compressor. Such a total energy system might be used to provide all power, light, heating and cooling for a hotel, school, shopping center or hospital. Gas turbine exhaust temperatures are typically in the range of 750° to 1,000° F. and therefore may be considered to be in the medium temperature range, requiring no special materials or alloy steels in the heat exchanger 16.
  • the housing 11 and convection heat transfer chamber 12 are generally rectangular in design having a relatively greater width than depth to accommodate the elongated evaporator sections 24 of the heat pipe assembly 16.
  • the inlet port 18 is connected to the convection heat transfer chamber 12 by means of an inlet transition shroud 26, and the exhaust port is connected to the convection heat transfer chamber by means of an exhaust transition shroud 28.
  • the housing 11 and convection heat transfer chamber 12 are supported at an upright position on a support skid or foundation frame 30.
  • the steam boiler tank 14 is supported in an elevated position on the skid 30 by means of vertical I-beams 32, horizontal I-beams 34, and angle plates 36 in a position directly adjacent to the convection heat transfer chamber 12 and overlying the inlet transition shroud 26 and inlet port 18.
  • This particular physical arrangement of the major components of the heat recovery system 10 is required because of the elongated geometry of the heat pipe assembly 16 and the requirement that the condenser section of each heat pipe be physically disposed within the steam boiler tank 14.
  • the steam boiler tank 14 is generally cylindrical in construction and includes hemispherical end covers 38 welded at each end. According to a typical arrangement, the waste heat recovery system is designed to produce 2 ⁇ 10 6 BTU per hour of saturated steam at 100 psi. Therefore a conventional construction material such as mild steel may be utilized to construct the steam boiler tank 14 for operation in this pressure range including a conservative pressure safety factor.
  • the steam boiler tank 14 is equipped with a conventional relief valve 40, pressure gauge 41, and a steam discharge pipe 42 for conveying steam 43 is disposed along the upper top surface of the tank. Also, the steam boiler tank 14 is equipped with a water level control 44 which includes a sight glass 56 and a low water cut-off transducer 48.
  • a condensate collecting tank 50 is filled by condensate 51 through a condensate return line 52 from the process which utilizes the steam generated by the system which may be, for example, a steam turbine driven alternating current generator (not shown).
  • supplemental makeup water may be required where an insufficient amount of condensate is available.
  • Condensate or makeup water accumulated in the collecting tank is conveyed to the boiler tank 14 by means of a water pump 54 and a fill line 56 which projects through the side of the steam boiler tank 14 and directs the flow downwardly as indicated by the arrow 58 as can best be seen in FIGS. 1 and 2 of the drawings.
  • This flow arrangement for water discharged into the steam boiler tank 14 helps create circular current flow within the volume of water 62 in cooperation with movement of bubbles of steam rising from the condenser end portions of the heat pipe assembly 16 as indicated by the arrow 64.
  • the circular flow of currents within the volume of water 62 provides that incoming water will be mixed uniformly within the boiler tank thereby promoting the production of steam at a relatively constant rate.
  • this inlet arrangement mixes the incoming water so that no cold streams flow directly onto weld areas which are sensitive to thermal shock.
  • An important feature of the steam boiler tank 14 is the provision of a pressure header plate 66 in a rectangular opening in one side of the tank.
  • the pressure header plate 66 serves as the interface between the condenser section of the heat pipe assembly 16 which is disposed entirely within the steam boiler tank 14 and the evaporator section of the heat pipe assembly which is disposed within the convection heat transfer chamber 12.
  • Each heat pipe in the heat pipe assembly 16 passes through a circular opening within the pressure header plate 66 and is joined to the surrounding portions of the pressure header plate by means of a conventional pressure sealing technique such as explosive bonding.
  • the fluid-tight seal produced by this technique ensures that the heated waste gas stream and the water will be physically isolated from each other.
  • the heat pipe assembly 16 comprises a rectilinear array of heat pipes 68 which are arranged in rows and columns according to a staggered pattern.
  • the heat pipes 68 have identical construction as illustrated in FIG. 4 and as described in U.S. Pat. No. 4,020,898 by George M. Grover and assigned to the assignee of the present invention, which is hereby incorporated by reference.
  • Other heat pipe constructions such as illustrated in U.S. Pat. No. 3,865,184 by George M. Grover and assigned to the assignee of the present invention, which is hereby incorporated by reference, may also be used to good advantage.
  • the preferred heat pipe of the present invention is indicated generally at 68 in FIG. 4 of the drawing.
  • the heat pipe includes an outer tubular envelope 70 which is typically a tubular member having a length many times greater than its cross-sectional width.
  • the outer tubular envelope 70 will be at least about eight feet in length and will have an inside diameter of about one-half to one inch. Such dimensions are mentioned as being typical only, it being understood that the overall length and diameters of such heat pipes can vary over wide ranges depending upon the particular application. While the illustrated heat pipe 68 is shown having a generally cylindrical tubular member 70 as the outer tubular envelope, it is to be understood that various other geometric shapes may be utilized such as rectangular or square cross-sectional tubular members.
  • the cylindrical tubular member 70 can be readily and economically formed into the heat pipe 68 for use in this invention.
  • the outer tubular member 70 is fabricated from a thermally conductive material such as copper, aluminum, or steel and the like, in order that thermal energy can be passed into and out of the interior of the heat pipe through the walls of the outer tubular member 70.
  • a plurality of conventional, thermally conductive heat exchanger fins 72 can be mounted at axially spaced points on the exterior of the tubular envelope 70 in such a manner as to provide good heat transfer between the fin and the envelope. This increases the effective area over which convection heat transfer occurs. Such fins have been found to increase the thermal energy transfer efficiency especially for gaseous steam-to-wall transfer. The fins can usually be eliminated where the heat exchange in made with a liquid rather than a gas. In the modular heat pipe assembly 16 as shown in FIG. 2, each of the evaporator sections 24A, 24B, and 24C contain progressively more heat exchanger fins 72 to achieve uniform heat transfer since the temperature of the heated waste gas stream decreases as it passes through each modular section.
  • the hot gas entrained solids should be considered in selecting the external fin configuration.
  • Natural gas fueled gas turbines produce a very clean exhaust, consequently high, closely spaced fins may be used, up to a fin spacing of ten fins per inch. Fin height, while adding to total surface, reduces fin efficiency because of the longer thermal path. High fins also increase through flow area or gas passage area. All of these factors must be balanced in a design for the most effective use of the heat pipes.
  • the heat pipes 68 are typically one inch OD carbon steel arranged on two inch centers and two inches between rows in a staggered array as can best be seen in FIGS. 1 and 3 of the drawing.
  • eight fins 72 of 0.024 inch mild steel with an aluminized surface are explosively bonded to the outer tubular member 70.
  • the opposite ends of the tubular member 70 are hermetically sealed by end caps 74.
  • the tubular envelope 70 is evacuated through a fitting provided on the end cap 74. Thereafter, the envelope 70 is filled with a liquid phase/vapor phase working fluid (not shown) such as a commercial refrigerant R12 or toluene.
  • the end cap 74 is the permanently sealed by crimping, soldering or welding.
  • the quantity of working fluid that is utilized in the heat pipe has been found to be relatively important for efficient operation. It has been determined that the heat transfer capability of the heat pipes 68 is maximized if the quantity of the working fluid in the heat pipe is such that the liquid phase is present in an amount of from about 40 to about 75 percent of the volume of the tubular envelope 22 at the desired operating temperatures.
  • each heat pipe 68 which are disposed wholly within the convection heat transfer chamber 12 collectively constitute an evaporator section as indicated by the dashed line 76.
  • the opposite end sections of each heat pipe 68 which are wholly disposed within the steam boiler tank 14 collectively constitute a condenser section for the heat pipe assembly 16 as illustrated by the dashed line 78 as can best be seen in FIG. 2 of the drawing.
  • the heat pipe assembly 16 transfers very large quantities of thermal energy between the evaporator section 76 and the condenser section 78 by the closed cycle movement of the working fluid as it is vaporized in the evaporator section and moves to the condenser section where it is condensed and returns to the evaporator.
  • the magnitude of the thermal energy which can be exchanged for a given arragy of heat pipes can be increased by elevating the condenser section 78 at an angle ⁇ with respect to the evaporator section 76 as shown in FIG. 2.
  • at least a portion of the working fluid liquid contained within the evaporator section will be vaporized and the vaporized portion will rise to the relatively cool condensor section of the heat pipe assembly where it is condensed and returns by gravity flow. Because of the phase change of the working fluid from a liquid to a vapor and then back to a liquid, large quantities of thermal energy are transferred between the evaporator section and the condenser section of the heat pipe.
  • a liquid phase return conduit or flow separator 80 is disposed within the tubular envelope 70 and extends from the evaporator section 76 to the condenser section 78.
  • the liquid phase return conduit 80 is a conduit that preferably has open ends to allow liquid phase working fluid to flow into the upper end of the liquid phase return conduit and then downwardly through the conduit to exit out the lower open end of the conduit into the evaporator section of the heat pipe.
  • liquid phase of the working fluid that is either swept or transported upwardly into the condenser section 78, as well as the liquid phase which forms upon the condensation of the vaporized working fluid in the condenser section, will enter the open end of the liquid phase return conduit 80 and will flow by gravity downwardly to the evaporator section wherein additional thermal energy, passing through the walls of the evaporator section, will cause evaporation of a portion of the working fluid with the vaporized portion flowing upwardly to the condenser section 78 in the space surrounding the outside of the liquid phase return conduit.
  • the heat pipe-flow separator combination described above is characterized by two distinctly different operating modes depending upon the angle of inclination of the heat pipe relative to the horizontal. These two operating modes are the evaporation/condensation mode and the "bubble" mode in which long bubbles of vapor displace slugs of liquid from the evaporatorsection to the condenser section. This reduces the vapor transport because the velocity of the bubbles is substantially less than that of a pure vapor stream. On the other hand, the transport of liquid is greatly increased. Since there is a finite temperature drop along the pipe, there is a large increase in the sensible heat transferred to compensate for the decrease in latent heat transfer associated with the decreased vapor being transported.
  • the heat pipe-flow separator combination operates in the evaporation/condensation mode, has good efficiency and a capacity several times greater than the non-flow separator heat pipe. At higher angles of inclination the capacity increases more slowly.
  • the temperature difference between the waste heat gas stream and the desired steam temperature is small, therefore high efficiency is desirable, and operation at angles of inclination at or below 35 degrees is preferred.
  • liquid phase return conduit 80 which provides a separate flow path with respect to the outer tubular envelopes 70, thereby thermally isolating the walls of the outer tubular envelope 70 with respect to the condensate working fluid which is conveyed through the liquid phase return conduit 80.
  • the liquid phase return conduit 80 is, of course, not a pressure member and may be formed of any suitable material, such as thin walled metal tubes of copper, aluminum, steel or the like.
  • the preferred length of the liquid phase return conduit 80 is from about 65 to about 85 percent of the length of the interior of the outer tubular envelope 70. In some instances, especially at higher angles of inclination , the liquid phase return conduit 80 can be shortened somewhat in the evaporator section and may extend into the evaporator section for a distance of down to about 15 percent of the length of the evaporator section.
  • the heated waste gas stream 20 would be provided by a clean source of hot air.
  • the heated waste gas 20 will be composed of air, combustion products, ash carryover, and other contaminants. Therefore, the heat pipe assembly 16 must be cleaned periodically to prevent fouling of the heat transfer fins 72.
  • Conventional soot blowers (not shown) can be utilized for this purpose.
  • one of the hemispherical end covers 38 may be provided with a bolted flange access plate (not shown) to permit quick removal for cleaning and inspection of the condenser assembly 78.
  • Flow of the heated waste gas stream 20 through the convection heat transfer chamber 12 is regulated by means of a face damper assembly 82, a bypass damper assembly 84 and an ambient air damper assembly 86.
  • the face damper and bypass damper assemblies are substantially identical in construction and include a number of adjustable vanes 88 which are generally horizontally disposed within the convection heat transfer chamber 12.
  • the face damper 82 assembly extends beneath the evaporator section 76 of the heat pipe assembly 16 and when closed completely blocks the flow of air through the evaporator section. Operation of the face damper assembly 82 in the closed position is desirable in an emergency situation brought about by a low water or a high pressure cutout alarm.
  • the face damper assembly is closed and the bypass damper 84 is completely opened thereby permitting the heated gas stream 20 to flow around the evaporator section 76 and through the exhaust port 22 substantially without exchanging heat with the evaporator section.
  • the vanes 88 also serve to promote heat transfer by causing turbulent flow of the heated gas stream 20 through the evaporator section 76.
  • the ambient air damper assembly 86 is provided in order to admit the flow of ambient air as represented by the arrow 90 in FIG. 1 into the convection heat transfer chamber 12 when it is desired to reduce the temperature of the incoming heated waste gas stream 20 and also to increase the mass flow across the evaporator section 76.
  • the waste heat recovery system 10 is illustrated in a gas-to-water heat exchange arrangement with regeneration of exhaust waste gas flow after heat exchange has taken place.
  • This arrangement is typically utilized when the incoming heated waste gas flow 20 is at a temperature above the effective operating range of the heat pipe assembly 16. The temperature is reduced and the mass flow is increased by recycling a fraction of the heated waste gas stream 20 after it has passed through the convection heat transfer chamber 12.
  • a fraction 92 of the exhaust heated waste gas stream 20 is circulated through a regeneration conduit 94 which is connected in fluid communication with the exhaust port 22.
  • the fraction 92 of the waste gas stream 20 is circulated by a forced draft fan 96 through the regeneration conduit 94 which is connected at its other end in fluid communication with the inlet port 18.
  • the fraction 92 preferably is mixed with the incoming flow 20 in a mixing chamber 95 so that the temperature of the incoming flow 20 is reduced to an operating temperature which is compatible with the operating range of the working fluid.
  • the magnitude of the fraction 92 of the waste gas stream which is recycled may be controlled by adjusting the speed of the forced draft fan 96.
  • superheated steam may be produced by connecting the exhaust port 22 of a first convection heat transfer chamber designated as 12U, referring to its position as being upstream relative to the inlet port 18 of a second convection heat transfer chamber 12D, referring to its relative position as being downstream.
  • the first and second convection heat transfer chambers 12U, 12D are connected in series fluid communication with each other whereby the heated waste gas stream 22 first passes over the evaporator section 76 of the upstream convection heat transfer chamber 12U and then passes over the evaporator section 76 of the downstream convection heat transfer chamber 12D whereupon it is conveyed through the exhaust port 22 to be discharged into the atmosphere.
  • a substantial amount of heat is transferred in the evaporator section 76 in the upstream convection heat transfer chamber 12U, for example at temperatures of 1000° F. and above for producing superheated steam, and thereafter transferring heat at a substantiallyreduced temperature, for example in the range of 700° or lower in the downstream convection heat transfer chamber 12D for producing saturated steam.
  • the working fluid in each of the evaporator sections is of course chosen to be compatible with the expected operating temperature range.
  • Saturated steam is conducted through the steam discharge pipe 42 to the boiler tank 14U of the upstream heat recovery system 10. There the saturated steam flows over a condenser section 78U which may include fins 72 for enhancing the heat transfer, thereby producing superheated steam which is conveyed through a superheated steam discharge pipe 98.
  • working fluid such as water, aliphatic hydrocarbons, aromatic hydrocarbons, halogen substituted materials, such as freon, refrigerants and the like, can be used.
  • freon materials such as refrigerant R12, benzene, toluene and the like.
  • the heat pipes 68 of the heat pipe assembly 16 generally comprise straight tubular pipes.
  • the heat pipes 68 in the heat pipe assembly 16 are disposed in parallel with each other and the assembly is oriented whereby the axis of each heat pipe will be inclined at an angle ⁇ above the horizontal to position the condenser section 78 above the evaporator section 76 (see FIG. 2). It has been found that the preferred range of the angle of inclination is between about 15 degrees to about 35 degrees above the horizontal.
  • the present invention comprises a unique waste heat recovery system having substantially improved operating characteristics over conventional systems.
  • the modular arrangement of the heat pipe assembly 16 permits each evaporator section 24A, 24B and 24C to contain different numbers of fins 72. Since the temperature of the heated waste gas stream 20 decreases as it passes through each modular evaporator section of the evaporator 76 the first evaporator section 24A will need fewer fins 72 than the last evaporator section 24C in order that the heat pipes in each evaporator section will transfer substantially the same quantity of heat. This freedom of choice of fin area for the modular evaporator sections permits many evaporator sections to be stacked to that the amount of heat transferred from the waste gas stream can be maximized.
  • the heat pipes extend freely into the boiler tank 14 and are sealed into the header plate 66 which permits free expansion without mechanical strain.
  • the outside portions of the heat pipes in the condenser section can be grooved or knurled to provide a heat transfer surface which enhances nucleate boiling of the water at the heat transfer surface.
  • fins may be attached to the condenser section end portions for superheat applications as illustrated in FIG. 6 of the drawing. Because tubes are not terminated in a manifold, it is possible to clean the heat transfer surfaces at regular maintenance intervals to keep the heat transfer surface in excellent condition.
  • the volume at the bottom of the boiler tank 14 conveniently serves as a "mud drum” volume, and additional flush-clean holes may be provided at various places in the tank to permit cleaning without complete disassembly.
  • One of the end cover plates can be sealed against the end of the boiler tank 14 by a bolted flange construction which allows quick removal for cleaning and inspection.
  • the boiler tank 14 may be used for purposes other than steam production.
  • the system may be used for vaporization of a flammable working fluid such as toluene for a waste heat Rankine cycle power system which requires complete isolation from the heated gas stream. Otherwise there would be an extremely hazardous possibility of venting the flammable material into the hot gas stream in the event of a leak of the system.
  • Complete isolation is provided by the union of the header plate 66 with each of the heat pipes 68 which are closed at their end portions and which operate at relatively low pressures.
  • the structure and operation of the heat pipe boiler of the present waste recovery system is analagous to a "single ended fire tube" boiler arrangement. It has the advantages of simplicity of construction, stability of operation, cleaning accessibility and reserve for demand variations. In addition, there is complete isolation of one fluid stream from the other.
  • the performance of the waste heat recovery system as a steam boiler is relatively high. Approximately 80 to 85 percent of the usable heat from a 1000° F. gas stream can be used to produce 100 psia steam. In other words, the 1000° gas stream can be cooled to about 450° F. in this stream boiler arrangement.

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  • Engineering & Computer Science (AREA)
  • Physics & Mathematics (AREA)
  • General Engineering & Computer Science (AREA)
  • Thermal Sciences (AREA)
  • Mechanical Engineering (AREA)
  • Sustainable Development (AREA)
  • Life Sciences & Earth Sciences (AREA)
  • Sustainable Energy (AREA)
  • Geometry (AREA)
  • Chemical & Material Sciences (AREA)
  • Combustion & Propulsion (AREA)
  • Heat-Exchange Devices With Radiators And Conduit Assemblies (AREA)
  • Waste-Gas Treatment And Other Accessory Devices For Furnaces (AREA)
US05/849,987 1977-11-09 1977-11-09 Waste heat boiler Expired - Lifetime US4482004A (en)

Priority Applications (8)

Application Number Priority Date Filing Date Title
US05/849,987 US4482004A (en) 1977-11-09 1977-11-09 Waste heat boiler
JP3357978A JPS5469854A (en) 1977-11-09 1978-03-23 Apparatus for and method of transmitting thermal energy from flow of heated gas to liquid
FR7809345A FR2408805A1 (fr) 1977-11-09 1978-03-30 Procede et installation de recuperation de chaleur
DE19782820734 DE2820734A1 (de) 1977-11-09 1978-05-12 Abwaermespeicher
CA315,907A CA1123690A (fr) 1977-11-09 1978-11-07 Chaudiere a recuperation de chaleur, et echangeur connexe
EP78101332A EP0001844B1 (fr) 1977-11-09 1978-11-08 L'appareil pour la récupération de la chaleur et une méthode de production de vapeur
DE7878101332T DE2862224D1 (en) 1977-11-09 1978-11-08 Apparatus for recovering heat and process for producing steam
US06/496,234 US4621681A (en) 1977-11-09 1983-05-19 Waste heat boiler

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
US05/849,987 US4482004A (en) 1977-11-09 1977-11-09 Waste heat boiler

Related Child Applications (1)

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US06/496,234 Continuation US4621681A (en) 1977-11-09 1983-05-19 Waste heat boiler

Publications (1)

Publication Number Publication Date
US4482004A true US4482004A (en) 1984-11-13

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ID=25306990

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US05/849,987 Expired - Lifetime US4482004A (en) 1977-11-09 1977-11-09 Waste heat boiler

Country Status (6)

Country Link
US (1) US4482004A (fr)
EP (1) EP0001844B1 (fr)
JP (1) JPS5469854A (fr)
CA (1) CA1123690A (fr)
DE (2) DE2820734A1 (fr)
FR (1) FR2408805A1 (fr)

Cited By (21)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4691666A (en) * 1984-04-30 1987-09-08 Stratus Corporation Liquid heater with closed loop heat transfer system
US4759313A (en) * 1987-10-30 1988-07-26 Shell Oil Company Ethylene oxide process improvement
US4871522A (en) * 1988-07-25 1989-10-03 The Babcock & Wilcox Company Combined catalytic baghouse and heat pipe air heater
WO1994020807A1 (fr) * 1993-03-05 1994-09-15 Sen Nieh Procede et dispositif d'echange thermique tourbillonnaire
US5383341A (en) * 1991-07-23 1995-01-24 Uri Rapoport Refrigeration, heating and air conditioning system for vehicles
USRE35283E (en) * 1988-11-01 1996-06-25 Helmich; Arthur R. High efficiency water distiller
US5947111A (en) * 1998-04-30 1999-09-07 Hudson Products Corporation Apparatus for the controlled heating of process fluids
US20040035131A1 (en) * 2002-05-28 2004-02-26 Gordon Latos Radiant heat pump device and method
US7017529B1 (en) * 2005-06-16 2006-03-28 H2Gen Innovations, Inc. Boiler system and method of controlling a boiler system
US20070245981A1 (en) * 2006-04-24 2007-10-25 Industrial Technology Research Institute Water heater and method of operating the same
US20080121379A1 (en) * 2006-11-28 2008-05-29 Otv Sa S.A. Evaporator
EA010144B1 (ru) * 2007-01-26 2008-06-30 Открытое Акционерное Общество "Уралэнергоцветмет" Котел-утилизатор
US20090133642A1 (en) * 2007-11-22 2009-05-28 Noritz Corporation Latent heat recovery-type water heater
US20090288813A1 (en) * 2008-05-26 2009-11-26 Daesung Industrial Corporation Structure of Heat Exchange Apparatus for Gas Boiler
US20110061386A1 (en) * 2009-09-15 2011-03-17 General Electric Company Heat pipes for transferring heat to an organic rankine cycle evaporator
CN102022822A (zh) * 2011-01-05 2011-04-20 李显峰 高效节能热管锅炉
US20120047889A1 (en) * 2010-08-27 2012-03-01 Uop Llc Energy Conversion Using Rankine Cycle System
US20130269907A1 (en) * 2012-03-17 2013-10-17 Econotherm Uk Limited Steam-to-gas heat exchanger
CN105486133A (zh) * 2015-12-31 2016-04-13 天津君议台科技发展有限公司 热管烟气余热回收装置及工作介质
WO2018018102A1 (fr) * 2016-07-27 2018-02-01 Freire Martins Alberto Échangeur et récupérateur de chaleur utilisé dans un système de chauffage industriel pour l'eau potable
US10077913B2 (en) * 2016-11-13 2018-09-18 Susan Jane Gold Energy transfer system (ETS)

Families Citing this family (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE2926578C2 (de) * 1979-06-30 1983-12-15 Wieland-Werke Ag, 7900 Ulm Wärmeübertragungseinrichtung
US4426959A (en) * 1980-07-01 1984-01-24 Q-Dot Corporation Waste heat recovery system having thermal sleeve support for heat pipe
US4524822A (en) * 1980-12-29 1985-06-25 Wieland-Werke Ag Safety heat-transmitting device
JPS58148539U (ja) * 1982-03-29 1983-10-05 工業技術院長 熱水発生器
FR2836715B1 (fr) * 2002-03-04 2004-06-25 Brunel Bureau Et Chaudiere a vapeur pour la production de vapeur surchauffee
CN103949484B (zh) * 2014-04-09 2016-01-20 莱芜钢铁集团有限公司 冷床余热回收利用装置
CN111927586A (zh) * 2020-07-03 2020-11-13 东方电气集团东方汽轮机有限公司 一种用于大型背压式汽轮机乏汽回收的四流程回收器

Citations (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB189418365A (en) * 1894-09-28 1894-12-01 Ludlow Patton Perkins Improvements in Steam or other Fluid Boilers.
US1524520A (en) * 1924-06-07 1925-01-27 Junkers Hugo Heat-exchange apparatus
US2153942A (en) * 1937-02-03 1939-04-11 Jr Jack J Spalding Heat exchanging apparatus
US3018087A (en) * 1958-04-11 1962-01-23 Hexcel Products Inc Heat transfer panel
US3779310A (en) * 1971-04-05 1973-12-18 G Russell High efficiency heat transit system
US3854454A (en) * 1973-11-01 1974-12-17 Therma Electron Corp Heat pipe water heater
US4040477A (en) * 1976-06-17 1977-08-09 Garberick Thayne K Heat recovery apparatus

Family Cites Families (10)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
FR542146A (fr) * 1921-10-10 1922-08-05 Naamlooze Vennootschap Fabriek Chaudière à vapeur
DE537771C (de) * 1927-10-14 1931-11-07 Cie Des Surchauffeurs Dampfkessel mit mittelbarer Beheizung durch ein Hilfsmittel
US1870009A (en) * 1928-07-27 1932-08-02 Superheater Co Ltd Waste heat boiler
FR859930A (fr) * 1939-06-07 1941-01-02 Air France Perfectionnements apportés aux générateurs et échangeurs de chaleur et aux installations de chauffage comportant de semblables dispositifs
CH334080A (de) * 1954-06-05 1958-11-15 Becke Ivo Rekuperator, insbesondere für Gase hoher Temperaturen
GB821487A (en) * 1956-12-29 1959-10-07 Vorkauf Heinrich Exhaust gas steam boilers installed after internal combustion engines
FR1294211A (fr) * 1961-04-11 1962-05-26 Comeconomiseur Cie Francaise D Perfectionnements à la construction des échangeurs de chaleur à tubes indépendants
JPS49125372U (fr) * 1973-02-20 1974-10-26
JPS50118102A (fr) * 1974-03-04 1975-09-16
SE395055B (sv) * 1975-11-04 1977-07-25 Svenska Flaektfabriken Ab Anordning for atervinning av verme ur fran en lokal bortford franluft till inford tilluft

Patent Citations (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB189418365A (en) * 1894-09-28 1894-12-01 Ludlow Patton Perkins Improvements in Steam or other Fluid Boilers.
US1524520A (en) * 1924-06-07 1925-01-27 Junkers Hugo Heat-exchange apparatus
US2153942A (en) * 1937-02-03 1939-04-11 Jr Jack J Spalding Heat exchanging apparatus
US3018087A (en) * 1958-04-11 1962-01-23 Hexcel Products Inc Heat transfer panel
US3779310A (en) * 1971-04-05 1973-12-18 G Russell High efficiency heat transit system
US3854454A (en) * 1973-11-01 1974-12-17 Therma Electron Corp Heat pipe water heater
US4040477A (en) * 1976-06-17 1977-08-09 Garberick Thayne K Heat recovery apparatus

Cited By (27)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4691666A (en) * 1984-04-30 1987-09-08 Stratus Corporation Liquid heater with closed loop heat transfer system
US4759313A (en) * 1987-10-30 1988-07-26 Shell Oil Company Ethylene oxide process improvement
US4871522A (en) * 1988-07-25 1989-10-03 The Babcock & Wilcox Company Combined catalytic baghouse and heat pipe air heater
USRE35283E (en) * 1988-11-01 1996-06-25 Helmich; Arthur R. High efficiency water distiller
US5383341A (en) * 1991-07-23 1995-01-24 Uri Rapoport Refrigeration, heating and air conditioning system for vehicles
WO1994020807A1 (fr) * 1993-03-05 1994-09-15 Sen Nieh Procede et dispositif d'echange thermique tourbillonnaire
US5947111A (en) * 1998-04-30 1999-09-07 Hudson Products Corporation Apparatus for the controlled heating of process fluids
US20040035131A1 (en) * 2002-05-28 2004-02-26 Gordon Latos Radiant heat pump device and method
US20070012433A1 (en) * 2002-05-28 2007-01-18 Latos Gordon D Radiant heat pump device and method
US7017529B1 (en) * 2005-06-16 2006-03-28 H2Gen Innovations, Inc. Boiler system and method of controlling a boiler system
WO2007001475A1 (fr) * 2005-06-16 2007-01-04 H2Gen Innovations, Inc. Systeme de chaudiere et procede de commande d'un systeme de chaudiere
US20070245981A1 (en) * 2006-04-24 2007-10-25 Industrial Technology Research Institute Water heater and method of operating the same
US7434545B2 (en) * 2006-04-24 2008-10-14 Industrial Technology Research Institute Water heater and method of operating the same
US20080121379A1 (en) * 2006-11-28 2008-05-29 Otv Sa S.A. Evaporator
EA010144B1 (ru) * 2007-01-26 2008-06-30 Открытое Акционерное Общество "Уралэнергоцветмет" Котел-утилизатор
US20090133642A1 (en) * 2007-11-22 2009-05-28 Noritz Corporation Latent heat recovery-type water heater
US8210132B2 (en) * 2007-11-22 2012-07-03 Noritz Corporation Latent heat recovery-type water heater
US8191512B2 (en) * 2008-05-26 2012-06-05 Daesung Industrial Corporation Structure of heat exchange apparatus for gas boiler
US20090288813A1 (en) * 2008-05-26 2009-11-26 Daesung Industrial Corporation Structure of Heat Exchange Apparatus for Gas Boiler
US20110061386A1 (en) * 2009-09-15 2011-03-17 General Electric Company Heat pipes for transferring heat to an organic rankine cycle evaporator
US8434308B2 (en) * 2009-09-15 2013-05-07 General Electric Company Heat pipes for transferring heat to an organic rankine cycle evaporator
US20120047889A1 (en) * 2010-08-27 2012-03-01 Uop Llc Energy Conversion Using Rankine Cycle System
CN102022822A (zh) * 2011-01-05 2011-04-20 李显峰 高效节能热管锅炉
US20130269907A1 (en) * 2012-03-17 2013-10-17 Econotherm Uk Limited Steam-to-gas heat exchanger
CN105486133A (zh) * 2015-12-31 2016-04-13 天津君议台科技发展有限公司 热管烟气余热回收装置及工作介质
WO2018018102A1 (fr) * 2016-07-27 2018-02-01 Freire Martins Alberto Échangeur et récupérateur de chaleur utilisé dans un système de chauffage industriel pour l'eau potable
US10077913B2 (en) * 2016-11-13 2018-09-18 Susan Jane Gold Energy transfer system (ETS)

Also Published As

Publication number Publication date
FR2408805A1 (fr) 1979-06-08
EP0001844A2 (fr) 1979-05-16
EP0001844A3 (en) 1979-05-30
FR2408805B1 (fr) 1983-01-21
JPS5760558B2 (fr) 1982-12-20
EP0001844B1 (fr) 1983-04-06
JPS5469854A (en) 1979-06-05
DE2820734A1 (de) 1979-05-10
CA1123690A (fr) 1982-05-18
DE2862224D1 (en) 1983-05-11

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